The present invention relates to an elastically deformable fender. As the elastically deformable fender, a so-called V-shaped fender has long been used widely. The V-shaped fender, as shown in FIG. 9, includes an elongated body, wherein a flat impact receiving section (1) for receiving the broadside, a pair of supporting sections (2) with legs diverging away from each other in an unfolded fan fashion and a fitting section (3) extending outwardly from the lower ends of each supporting section (2) being formed integrally, and has a substantially inverted V-shaped cross section.
Meanwhile, in the V-shaped fender aforementioned, when the impact receiving section (1) is compressed by an impact load of the hull of a ship, superfluous rubber in the impact receiving section (1) tends to expand outwardly into a space between the supporting sections (2), consequently, as shown by the dotted line in FIG. 9, curving the impact receiving section (1) in the direction of downward expansion of the center portion in the drawing at the start of the application of the impact load of the hull of the ship. Since the bending of the supporting sections (2) are accelerated by the curving as described above, the supporting sections (2) become bending from the start of the application of the impact load of the hull.
Then the supporting sections (2) bend and deform as continuously contacting the broadside as shown by a dotted single line in the drawing, reaching further limited range of deformation within a short period of time and cause a sudden rise of the reaction force relatively in a short time. This is exactly as shown in a performance curve (X) in FIG. 10, thereby it is clear that the sudden rise of the reaction force occurs when the magnitude of compression is approximately 40%. In order to improve the absorbing performance of the impact energy of the V-shaped fender, the starting time of the bending of the supporting sections (2) should be delayed as much as possible and the amount of deformation thereof should be larger by avoiding the contact between the broadside and the outer surface of the supporting sections (2).
In consideration of this fact, there has been proposed a fender having a center groove extending lengthwise on the top surface (i.e. contact surface with the broadside) of the impact receiving section (refer to Japanese Patent Publication No. 55-12923 and U.S. Pat. No. 3,820,495). Since the side portions on both sides of the center groove are compressed in a direction of the groove when the impact is applied according to said kind of the fender, the fender is influenced by the top surface area and variations of frictional coefficient of the broadside and hence the absorbing performance of the impact energy is not always stable (refer to the performance curves (Y) and (Z) in FIG. 10, wherein (Y) and (Z) representing the cases of small and large frictional coefficients, respectively).
In order to solve such problems as described above, the applicant has proposed a fender having a suitable ratio between the width of the impact receiving section and the span between the heels of the supporting sections, and the impact receiving section (1) with the thickness thereof being formed thick so as to clearly protrude outward from the supporting sections (refer to Japanese Patent Publication No. 56-9604, U.S. Pat. No. 4,267,792, British Pat. No. 2032050, F.R.G. Patent Offen No. 28566200A and French Pat. No. 2413584).
With this fender, it has been discovered that the similar curving as the state shown by the dotted lines in FIG. 9 has occurred again because of the fact that the distance between the upper ends of the supporting sections expanding inevitably when the improvement was made to reduce the surface pressure applied on the broadside by forming the impact receiving section widely and widening the top surface area thereof.
Since the curving of the impact receiving section cause the reduction in contact surface between the broadside and the impact receiving section in this way, the broadside is exposed to an excessive stress, which involves such a disadvantage in that the broadside will be susceptible to inflicting damage, denting the ship's hull in particular, in case of such a large ship as a tanker.
The present invention was made in view of this problem as described above in order to provide the elastically deformable fender the performance of absorbing the impact energy to the broadside of ships from inflicting damage with a simple structure.
The present invention relates to the elastically deformable fender comprising an impact receiving section having a flat contact surface with the broadside with predetermined thickness, a pair of supporting sections depending from the reverse side of the impact receiving section described above so as to diverge away from each other in an unfolded fan fashion and being formed integrally with the impact receiving section, and the fitting sections protruding outwardly from the ends of the supporting sections in parallel to the contact surface described above, wherein the thickness of the impact receiving section is formed thick so as to protrude from the supporting sections by the predetermined length and the width is formed smaller than the span between the heels of the supporting sections, while between the supporting sections on the reverse side of the impact receiving section a hollow portion is formed lengthwise for preventing the impact receiving section from curving.